The primary goal of this project is an understanding of collagen structure from the molecular to the fibril level. Emphasis is presently on two main aspects of the general problem. 1) Conventional and scanning transmission electron microscopy and analysis of micrographs to obtain quantitative data and reveal detail not obvious to the eye. 2) Three-dimensional computer models to study and illustrate structural features of collagen and molecular aggregates. Each of the above two approaches has led to the development of computer software that is being applied to other problems is protein chemistry. These include myosin structure and the computer analysis of two-dimensional gels of protein mixtures. A third aspect of the problem recently initiated is to analyze x-ray diffraction data as a means of selecting from among possible molecular packing models of collagen.